Error while connecting to AX using WPF ManagedHostControl, help?

Hello, I have a WPF control that I'm using as a ManagedHost control, and I added a Business Connector connection to display on the WPF control some records from AX 2012, when I run the ManagedHostControl from AX I get:

 Exception has been thrown by the target of an invocation.

Any idea on what might be happening? the ManagedHost control was working fine  beforing adding the Business Connector method, this is what I use to connect to AX, it works from Visual Studio, but not from DAX:

Axapta DynAx = new Axapta();

DynAx.Logon(null, null, null, null);

Thanks in advanced!